Gas lasers have been described in literature as well as methods of manufacturing the same. Relatively low powered gas lasers and methods of manufacturing the same have been described by Kolb, Jr. in U.S. Pat. No. 3,495,119 and by Hochuli et al in Relative Frequency Stability of Stable He-Ne Gas Laser Structures appearing in the IEEE Journal of Quantum Electronics, December 1971, pp 573-575. More particularly the laser body comprises a glass shell enclosing a plurality of communicating gas passages. At least two electrodes are provided for exciting the gas. One of the communicating gas passages comprises a relatively narrow plasma tube through which travel electrons emitted by one electrode. The electrons ionize a portion of the atoms of the gas creating the desired discharge and energy level population inversion. By providing a suitable resonant optical cavity a device is provided for supplying the well known laser light output. Although these devices are known to the art, and have been constructed and operated there are a number of problems related to this field which the art has not, up to this time, been capable of solving.
As can be expected there has been a continual striving to increase the operating lifetime of the laser. There are two factors which are particularly important to laser lifetime. One of these relates to the gradual destruction of the electrodes through normal use. Although the reasons for this destruction are not yet well known at least one factor in the destruction of the electrodes is the presence of impurities in the electrodes. Another factor governing laser lifetime is the leakage to and from the operating medium, i.e., the gases, through the seals. The use of epoxy seals has been wide spread in the art notwithstanding the knowledge that such seals do in fact leak.
Another difficulty which the art has sought to overcome, without success, are the numerous manual steps required in the manufacturing of such a laser. Prominent among these is the requirement for glass to be blown to provide the laser bodies. Those of ordinary skill in the art will understand the advantages to be gained by limitation of manual manufacturing steps, especially steps such as glass blowing. Further advantages could accrue if the glass blowing steps could be eliminated. Because of the use of glass blowing the art has seen fit to employ Pyrex glass by reason of that materials desirable qualities for the process of blowing. However, it is difficult to select suitable materials for sealing to Pyrex to effect a hard seal. For this reason, the art has employed soft seals such as epoxy, which, as has been mentioned above, introduced the leakage problems. Thus, eliminating the blowing steps allows advantages to be obtained beyond the mere elimination of manual manufacturing steps. That is, different materials can be employed whose characteristics provide still other advantages.
Another problem introduced by the glass blowing is that blown glass does not produce identical components from every operation. This has lead to difficulty in employing jigs and other fixtures in further manufacturing steps. For instance, the Kolb, Jr. apparatus requires a plurality of glass cylinders to be joined. The fact that the cylinders are formed by blowing may lead to difficulty in employing jigs and other fixtures in the joining operation and, if the jigs or fixtures are eliminated then the step of joining the different components becomes another manual operation with its own attendant difficulties.
A still further problem in the prior art has been the mechanical stability of the final product. For effective laser operation, of course, the plasma tube should remain linear and aligned with the mirrors and windows (if employed). The fragile nature of the blown glass components has introduced instability problems in that the possibilities of bending and fracture exist. This is especially important in some laser operations where temperature variations can induce thermal stresses.
It is therefore an object of the present invention to provide a method of manufacturing a gas laser body which employs a step of depositing a metallic layer to form the electrodes. This step allows greater control over the material eventually employed as the electrode compared to prior art processes which are not able to use deposition techniques.
It is another object of the present invention to provide a method of manufacturing a gas laser body which eliminates the necessity for glass blowing.
It is another object of the present invention to provide a method of manufacturing a glass laser body which employs material capable of providing a hard seal with relatively simple manufacturing techniques.
It is another object of the present invention to provide a gas laser and a method of manufacturing a gas laser which reduces the number of manual steps required in the manufacturing operation to thereby reduce manufacturing costs.
It is still another object of the present invention to provide a gas laser with a greater degree of stability over that shown in the prior art.